The assignee of the present application has filed a co-pending patent application entitled “Manually-Directed, Electronic Multi-Channel Electronic Pipetting System”, which was filed on even date herewith, by Julian Warhurst, Gary Nelson and Richard Cote, is based on U.S. Provisional Application No. 61/330,541, filed on May 3, 2010, and is herein incorporated by reference. The assignee has also filed another co-pending patent application entitled “Unintended Motion Control for Manually Directed Multi-Channel Electronic Pipettor, which was filed on even date herewith, by Julian Warhurst and Richard Cote, is based on U.S. Provisional Application No. 61/3340,545, filed on May 3, 2010, and is also incorporated by reference herein. The present invention pertains to a manually directed, multi-channel electronic pipettor as well, and in particular to features of the motion control system that facilitate precise positioning of the multi-channel pipetting head and the disposable pipette tips for aspiration and dispensing of liquid samples and reagents into and from an array of wells in a wellplate.
As is known in the art, a multi-well plate is a flat plate with multiple wells used as individual test tubes. The most common multi well-plates include 96-wells or 384-wells arranged in a rectangular matrix. ANSI has set standardized dimensions and SBS footprints for well-plates. For example, 96-well plate has eight rows and twelve columns of wells centered 9 mm centerline-to-centerline. A typical 384-well plate includes sixteen rows and twenty-four columns of wells with a centerline-to-centerline distance of 4.5 mm. Multi-well-plates with 1536-wells, and higher, are also available. Some multi well-plates are designed to hold larger volumes than the standard multi well-plate, yet maintain the standard centerline-to-centerline dimensions. These well-plates are commonly called deep well-plates. For purposes herein, the term multi-well plate to refer to both standard multi well-plates and deep well-plates. Assignee's manually-directed, electronic multi-channel pipetting system, as described in the above incorporated patent applications, is designed to transfer liquid samples from an array of wells in a standard multi-well plate or deep wellplate, or from a reagent reservoir to an array of wells in another standard wellplate or deep wellplate.
One of the advantages of the assignee's manually directed, electronic multi-channel pipetting system is the ability of the user to move the pipetting head, and hence the disposable pipette tips, in response to pressure exerted on the control handle. This feature of operation is significantly different than the operation of fully automated, high-throughput liquid handling systems. The multi-channel pipetting head in the assignee's manually directed system is mounted to a movable carriage that is attached to a tower. A deck having preferably two wellplate nesting receptacles is located in front of the tower and is accessible by the pipetting head. The tower contains a drive system to raise and lower the pipetting head to aspirate and dispense reagents and samples in the well-plates or reservoirs set in the nesting receptacles on the deck. The system also includes a drive system to move the tower, as well as the pipetting head, in a horizontal or X-axis direction. The control handle is preferably mounted to a load cell attached to the pipetting head, although it may be mounted in various other positions on the laboratory bench. The load cell detects force exerted on the control handle and outputs corresponding signals to the electronic motion control system. In use, the user grabs the control handle in a manner similar to when using a hand-held electronic pipettor. The user exerts pressure on the control handle and in turn the load cell transmits signals to the electronic motion control system to move the multi-channel pipetting head relative to the well-plates and reservoirs on the deck. As mentioned, in the preferred embodiment, a motorized vertical drive mechanism raises and lowers the pipetting head with respect to the wellplate deck and a motorized horizontal drive mechanism moves the tower and the pipetting head laterally, both in response to sensed force exerted on the control handle. If the user presses the control handle from left to right, the tower along with the pipetting head moves from left to right. If the user pulls the control handle upward or pushes downward on the control handle, the vertical drive mechanism raises or lowers the pipetting head accordingly.
The control handle and menu-driven software programming interface is quite similar to the control handle and programming interface on assignee's hand-held electronic pipettors, see e.g., U.S. Pat. No. 7,540,205, issuing Jun. 2, 2009, entitled “Electronic Pipettor”, based on application Ser. No. 11/856,231 by Gary E. Nelson, George P. Kalmakis, Kenneth Steiner, Joel Novak, Jonathon Finger, and Rich Cote, filed on Sep. 17, 2007, assigned to the assignee of the present application and incorporated herein by reference; and “Pipettor Software Interface”, application Ser. No. 11/856,232 by Gary Nelson, George P. Kalmakis, Gregory Mathus, Joel Novak, Kenneth Steiner and Jonathan Finger, filed Sep. 17, 2007, now U.S. Pat. No. 7,540,205, issued Jun. 2, 2009, and assigned to the assignee of the present application and incorporated herein by reference. One of the benefits of this similarity is that users which have become comfortable with the assignee's hand-held pipettors are able to easily cross-over to use the assignee's manually directed, electronic multi-channel pipetting system.